The present invention relates generally to a panoramic attachment optical system and a panoramic optical system, and more specifically to a panoramic attachment optical system and a panoramic optical system, each of small-format size and high resolving power, which are well suited for use on all sky cameras, all sky projectors, etc., designed to form on image plane an image having a full 360°-direction angle of view or project an image located on an image plane at a full 360°-direction angle of view.
Among prior optical systems using a reflection optical system to obtain a full 360°-direction (full-panoramic) image, there is one using a single reflecting surface such as that set forth in patent publication 1, one using two reflecting surfaces such as those set forth in patent publications 2 and 3, and one known as “Chameleon Eye®” available from Sony Corp.
Patent Publication 1
Japanese Patent No. 2925573
Patent Publication 2
JP(A)11-331654
Patent Publication 3
JP(A)2003-167195
With any of the prior optical systems that are not designed to form any intermediate image en route to the image plane, typically, that set forth in patent publication 1, a full 360°-direction image to be formed in ring form becomes a mirror image where heaven and earth change place.
A problem with the optical systems shown in patent publications 2 and 3 is that the reflecting optical system becomes bulky because the image of the entrance pupil of an image-formation optical system, too, is not formed in the reflecting optical system.
With “Chameleon Eye”, it is not easy to make the angle of view wide in the vertical direction with the result that the reflecting optical system becomes bulky, because light is reflected successively at reflecting surfaces positioned with the center axis interposed between them and so the entrance-side reflecting surface acts to limit the angle of view.
Such being the case, the primary object of the invention is to provide a panoramic attachment optical system and a panoramic optical system for taking an image having a full 360°-direction (full-panoramic) angle of view or projecting an image at a full 360°-direction (full-panoramic) angle of view, which have decreased size, minimized flare light and improved resolving power.